Manuherikia Group | |
---|---|
Stratigraphic range: Early-Middle Miocene | |
Type | Group |
Sub-units | Dunstan & Bannockburn Formations |
Lithology | |
Primary | Sandstone, shale |
Other | Coal |
Location | |
Location | South Island |
Coordinates | 44°54′S169°48′E / 44.9°S 169.8°E |
Approximate paleocoordinates | 49°42′S179°36′W / 49.7°S 179.6°W |
Region | Central Otago |
Country | New Zealand |
Extent | >5,600 km2 (2,200 sq mi) |
Type section | |
Named for | Lake Manuherikia |
The Manuherikia Group is a fluvial-lacustrine sedimentary fill in the Central Otago area of New Zealand, at the site of the prehistoric Lake Manuherikia. The area consists of a valley and ridge topography, with a series of schist-greywacke mountains at roughly ninety degrees to each other. The Manuherika Group occurs in the current basins, and occasionally on the mountains themselves.
One of the earliest geologists to work in the area, McKay, [1] understood that the Manuherikia Group was probably originally continuous. Although some workers came to believe the sediments were deposited in a series of small, interconnected basins between the mountain ranges, e.g. Park, [2] later workers, like Cotton [3] argued that the sediments had been isolated by later mountain growth. Douglas [4] placed the Manuherikia Group sediments into a coherent genetic context. He drew attention to Manuherikia Group sediments on the top of mountain ranges, and to the observation that sequences in distinct basins were similar. His conclusion was that the Manuherikia Group is the result of sedimentation in a single (except for the earliest stages) very large basin that was later intruded by the growth of the mountain ranges. This basin ultimately grew into a single huge lake – Lake Manuherikia – that extended over some 5,600 km2 (2,200 sq mi). [4]
Palynological work by Couper, [5] [6] Mildenhall, [7] Mildenhall and Pocknall [8] has indicated that the Manuherikia Group is basically Miocene in age. The plant macrofossils, common in the lower Manuherikia Group, are mostly Early Miocene, perhaps with some in the earliest Middle Miocene.
Following Douglas, [4] the primary subdivision of the Manuherikia Group is into a lower, fluvial (commonly with coal) Dunstan Formation and an upper, lacustrine Bannockburn Formation. The oldest unit of the Manuherikia Group is the Saint Bathans Member of the Dunstan Formation, consisting of the braided-river fill of valleys incised into the basement rocks. Traces of three St Bathans paleovalleys are known – one at Blue Lake, adjacent to St Bathans, is the best exposed. The St Bathans paleovalleys eventually filled, sedimentation spread out over a broader area, and the fluvial character became dominantly meandering. This material is grouped as the Fiddlers Member. Extensive coal swamps developed between the rivers and their flood basins.
Individual flood basin lakes began to coalesce into a true lacustrine system – Lake Manuherikia. Its muddy and sandy sediments are grouped as the Bannockburn Formation. Around the lake margins, distinctive shoreline facies developed. The most widespread of these is the Kawarau Member which contains diverse plant fossils. [9] Distinctive facies within the Kawarau Member have been termed the Cromwell Submember and the Ewing Submember. The Ewing is typically intercalated with the Lauder Member, an informal unit of the Bannockburn Formation. This contains a fossil fauna (the Saint Bathans Fauna) of birds, [10] fish, [11] and a crocodilian, [12] New Zealand's first known terrestrial mammal, [13] as well as bats. Stromatolites are also present. [14]
At two locations around the depocenter, river deltas developed and large thicknesses of coal built up on upper delta plains. These are termed the Blackstone Delta and Teviot Delta. Fully lacustrine conditions ensued with the submergence of these deltas and for much of the mid Miocene, Lake Manuherikia was without known bounds. Rising mountains in the Late Miocene-Pliocene eventually deluged Lake Manuherikia with gravel – the Maori Bottom, or Maniototo Conglomerate. [15]
An extremely diverse macroflora flora, based on well-preserved cuticle. There are two cycad-like taxa:
The conifers total 16 species in 12 genera, including:
Other gymnosperms:
Monocots include:
The dicots include:
Owlet-nightjars are small crepuscular birds related to the nightjars and frogmouths. Most are native to New Guinea, but some species extend to Australia, the Moluccas, and New Caledonia. A flightless species from New Zealand is extinct. There is a single monotypic family Aegothelidae with the genus Aegotheles.
Mystacinidae is a family of unusual bats, the New Zealand short-tailed bats. There is one living genus, Mystacina, with two species, one of which could have possibly become extinct in the 1960s. They are medium-sized bats, about 6 centimetres (2.4 in) in length, with grey, velvety fur.
The Saint Bathans mammal is a currently unnamed extinct primitive mammal from the Early Miocene of New Zealand. A member of the Saint Bathans fauna, it is notable for being a late-surviving "archaic" mammal species, neither a placental nor a marsupial. It also provides evidence that flightless fully terrestrial mammals did in fact once live in Zealandia. This is in contrast to modern New Zealand, where bats, cetaceans and seals are the only non-introduced mammals in the otherwise bird-dominated faunas.
Icarops is an extinct, possibly paraphyletic genus of mystacine bat with three described species. The genus is known from fossils found at Riversleigh, north-western Queensland, Bullock Creek, Northern Territory, and Lake Ngapakaldi to Lake Palankarinna Fossil Area South Australia Australia. The fossils date from the late Oligocene to early Miocene.
Galaxias bobmcdowalli is an extinct species of ray-finned fish in the genus Galaxias. It existed in what is now New Zealand in the early Miocene epoch. It was described by Werner Schwarzhans, R. Paul Scofield, Alan J. D. Tennyson, Jennifer P. Worthy and Trevor H. Worthy in 2012.
Prototroctes modestus is an extinct species of bony fish in the family Retropinnidae. It existed in what is now New Zealand in the early Miocene epoch. It was described by Werner Schwarzhans, R. Paul Scofield, Alan J. D. Tennyson, Jennifer P. Worthy and Trevor H. Worthy in 2012.
Prototroctes vertex is an extinct species of bony fish in the genus Prototroctes. It existed in what is now New Zealand in the early Miocene epoch. It was described by Werner Schwarzhans, R. Paul Scofield, Alan J. D. Tennyson, Jennifer P. Worthy and Trevor H. Worthy in 2012.
Nelepsittacus is a genus of extinct New Zealand parrots that is closely related to the genus Nestor. It consists of four species, of which three have been named so far. The species are all known from the early Miocene Saint Bathans Fauna from the Lower Bannockburn Formation in Otago in New Zealand.
Matuku otagoense, also referred to as the Saint Bathans heron, is an extinct genus and species of heron from the Early Miocene of New Zealand. It was described from fossil material collected in 2007 from the Saint Bathans fauna of the Bannockburn Formation in Otago, South Island. It was a contemporary of the much smaller Saint Bathans bittern, remains of which have been found in the same sediments. The genus name matuku is a Māori-language word meaning “heron” or "bittern". The specific epithet is a latinisation of the name of the Otago region where the descriptive material was collected.
Rupephaps taketake, also referred to as the Saint Bathans pigeon, is an extinct species of pigeon from the Miocene of New Zealand. It is the first species of columbid to be described from pre-Pliocene fossil deposits in the Australasian region.
The St Bathans fauna is found in the lower Bannockburn Formation of the Manuherikia Group of Central Otago, in the South Island of New Zealand. It comprises a suite of fossilised prehistoric animals from the late Early Miocene (Altonian) period, with an age range of 19–16 million years ago.
Manuherikia is a genus of extinct species of ducks from the Miocene of New Zealand. It was described from fossil material of the Saint Bathans Fauna, in the lower Bannockburn Formation of the Manuherikia Group, found by the Manuherikia River in the Central Otago region of the South Island. The genus name comes from the name of the geological formation in which the fossils were found and, ultimately, from the Manuherikia River and its valley.
Miotadorna is a genus of extinct tadornine ducks from the Miocene of New Zealand. It contains two species, M. sanctibathansi, and M. catrionae.
Kuiornis indicator is an extinct New Zealand wren (Acanthisittidae) known from the early Miocene St Bathans fauna in Central Otago. It is known from a holotype proximal right tarsometatarsus. Amongst acanthisittids it is most closely related to the living rifleman.
Hakawai is an extinct genus of prehistoric birds that lived during the early Miocene to middle Miocene in New Zealand. According to a 2015 paper, Hakawai melvillei was a representative of a large group of birds that comprises the seedsnipes of family Thinocoridae) and the plains-wanderer. This discovery sheds light on evolutionary processes at work when South America, Antarctica, Australia, and New Zealand were all parts of Gondwanaland.
Lake Manuherikia was a prehistoric lake which once stretched over some 5,600 square kilometres (2,200 sq mi) in what is now inland Otago in New Zealand's South Island. It stretched from Bannockburn and the Nevis valley in the west to Naseby in the east, and from the Waitaki valley in the north to Ranfurly in the south, including much of the area now referred to as the Maniototo. The lake existed from around 19 to 16 million years ago during the Miocene epoch, at which point New Zealand was significantly warmer than the present.
Heracles inexpectatus is a giant fossil parrot species from New Zealand, assigned to a monotypic genus Heracles, that lived during the early Miocene approximately 16 to 19 million years ago. The species was described from two tibiotarsus fossils discovered in 2008 at Saint Bathans, Otago, New Zealand. It is believed that the species stood up to 90 cm tall and weighed approximately 7 kg (15 lb). Initial analysis suggests that this parrot is from the order Psittaciformes and from the superfamily Strigopoidea, which consists of three confirmed primitive genera of parrots: Nestor, Strigops (Kākāpō) and the fossil Nelepsittacus. It may have been the ancestor of the kākāpō.
Noctilionoidea is a superfamily of bats containing seven families: Thyropteridae, Furipteridae, Noctilionidae, Mormoopidae, Phyllostomidae, Myzopodidae, and Mystacinidae.
Zealandornis is an extinct genus of zealandornithid bird from the early Miocene Bannockburn Formation of Otago, New Zealand. The genus contains a single species, Zealandornis relictus, known from a distal right humerus.
Notochen, also called the Bannockburn swan, is an extinct genus of anatid bird from the Early Miocene Bannockburn Formation of Otago, New Zealand. The genus contains a single species, Notochen bannockburnensis, known from various fossil material.
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